Award details

Starch granule and polymer initiation

Reference	BBS/E/J/0000A234
Principal Investigator / Supervisor	Dr Kay Trafford
Co-Investigators / Co-Supervisors
Institution	John Innes Centre
Department	John Innes Centre Department
Funding type	Research
Value (£)	173,366
Status	Completed
Type	Institute Project
Start date	19/09/2005
End date	18/09/2008
Duration	36 months

Abstract

Starch exists in the plastids of plants in the form of discrete granules of 1-100 micrometers in diameter. Important goals for research are to understand how starch is made, what controls how much starch is made in a plant cell, and how the size and properties of the starch granules are determined. Starch granules are insoluble and are composed of two sorts of glucose polymer called amylose and amylopectin. We understand reasonably well how the polymers in starch are made. Many of the starch biosynthetic enzymes have been identified and the genes encoding these have been cloned. In contrast, our knowledge of how the growth of a starch granule or the polymers within is initiated is poorly understood and lags behind our understanding of glycogen initiation. Glycogen accumulates in animals and yeast instead of starch and its initiation is known to require a protein primer called glycogenin. One possibility that we will explore in this proposal is that plants may have a primer similar to glycogenin, either for priming the initiation of granules or starch polymers or both of these. The primer in plants may be similar in sequence to glycogenin and we will explore the functions of such plant proteins using mutants that lack these glycogenin-like genes. Alternatively, the primer in plants may function similarly to glycogenin but have a very different amino acid sequence. To find such primers, we have looked for proteins that are present inside plastids where starch is made that have enzymatic properties similar to glycogenin. Two candidates have been found and their roles will be explored in this proposal. We will purify these proteins, determine their amino acid sequences and compare them to the sequences of animal and yeast glycogenins. We will also explore the roles of these proteins in starch biosynthesis, again using mutants that lack these proteins.

Summary

unavailable

Committee	Closed Committee - Plant & Microbial Sciences (PMS)
Research Topics	Crop Science, Plant Science
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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